Preheat oven to 375 degrees F.
Over low heat, melt the butter in a large skillet that can hold all ingredients.
Stir in the flour gradually, then the milk gradually, until the mixture is smooth.
Crumble the cheese into the mixture and stir until it has melted and become incorporated. Set aside.
Separate the eggs and whip the whites until they start to hold peaks.
The cheese mixture will have cooled sufficiently so you can first fold in the eggs yolks and then the egg whites.
Spray a round ceramic soufflé dish with cooking spray, preferably Pam. Pour in the mixture and bake for about 45 minutes or until the soufflé, which should have risen slightly, is turning a dark brown on top and has started to pull away from the sides of the dish.
Serve immediately with a side sauce of tomato salsa with diced vegetables (zucchini, onion, asparagus) and plenty of crusty bread.